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  <title>数组flat-ES10</title>
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<body>
  <script>
    //  flat    平
    // 将多维数组转化为低位数组
    // const arr = [1,2,3,4,[5,6]];
    // const arr = [1,2,3,4,[5,6,[7,8,9]]];
    // 参数为深度  是一个数字
    // console.log(arr.flat(2));

    // flatMap
    const arr = [1,2,3,4];
    // const result = arr.map(item => [item * 10]);    // [[10],[20],[30],[40]]
    const result = arr.flatMap(item => [item * 10]);   // [10, 20, 30, 40]

    console.log(result);

  </script>
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